Electric switch



April 1932- w. J. BAUROTH 1,853,251

ELECTRIC SWITCH Filed Oct. 23, 1928 2 Sheets-Sheet l 1e TI April 12, 1932. w J, BAURQTH 1,853,251

ELECTRIC'SWI'HGH Filed Oct. 23, H.928 2 Sheets-Sheet 2 Patented Apr. 12., 1932 UNITED STATES PATENT; OFFICE WALTER J. BAUROTH, OF COLUMBUS, OHIO, .ASSIGNOR TO THE JEFFREY MANUFACTUR- ING- COMIANY, OF COLUMBUS, OHIO, A CORPORATION OF OHIO ELECTRIC SWITCH Original application filed April 30, 1926, Serial No. 105,873. Divided and this application filed October 23,

1928. Serial No. 314,429.

The present invention relates to certain new and useful improvements in electric switches of the type adapted to be used in the explosive gas charged atmosphere of a coal mine.

- dental ignition.

It is the especial object of this invention to 7 provide an improved mechanism of the class described, which shall be reliable and eflicientin service, economical to manufacture, convenient for inspection and repair, and wherein the electric circuit can be closed only after the protective devices have been placed in protecting position, and the protective devices can be opened for inspection or repair only after the circuit has been broken.

The means whereby I attain this object are fully set forth in the following specification and illustrated in the accompanying drawings of which j Fig. 1 is 'a' plan view of the preferred embodiment of my invention showing the protective casing closed.

Fig. 2 is a sectional view taken along the line II-II- of Fig. 1.

Fig. '3 is an end elevation of the device shown in Figs. 1 and 2, with the protective casing open.

Fig. 4 is a cross-sectional view. similar to 740 Fig; 2, showing a modified form of the inven- 'tion.

ILike numerals refer to similar parts in the several figures.

' 'In my co-pending application, Ser. No.

105,873, filed Apr/ 30, 1926, of which this application is a division, claims were presented relating to a casing adapted to protect a circuit breaking switch, and other claims were presented relating to the combination of theswitch and easing. In that application I have elected to prosecute the claims relating to the casing per se, and in response to the requirement for division have presented the present application containing claims relating to the combination of the switch and casing.

In Figs. 1, 2 and 3, of the drawings I have shown the preferred embodiment of my invention. In these figures the numeral 1 refers to a box or casing which is adapted to en-.

close the devices which are to be protected. In the upper wall 2 of the casing is formed an opening through which access may be had to the apparatus within the casing. This opening is preferably, though not necessarily, circular in form, and is adapted to receive a cover plate 3 the edges of, which are shaped to contact with the edges of the upper wall 2 to form a gas tight joint. In the embodiment here shown the opening in the wall 2,.

and the cover plate are of circular form and upon their edges are formed cooperating screw threads 4 adapted, by their engagement to hold the cover plate securely in place. Radially extending ribs 5 formed on r the outer surface of the plate 3 afiord convenient means for the rotation of said plate to screw it into or out of closed position. Attached to the cover plate 3 at its center, is a pivot stud 6 which is journaled in a suitable.

aperture of the hinge arm 7 The hinge arm 7 is rotatable about a hinge pin 8 attached to suitable lugs 9 formed on the side wall 10 of the casing. Provision is made by a slot for limited movement of said arm transversely of the hinge pin 8. By this arrangement of parts the cover plate 3 may be moved, in parallelism, outwardly of the casing to clear the upper surface of the top wall 2, after.

, 11 extending longitudinal of the hinge arm 7 v a shaft 13 by the rotation of which the switch devices within the casing may be actuated. The bearings for the shaft 13 in the wall of the casing are arranged to form gas tight joints, but as such devices are well understood in the art their illustration and description is not thought to be required at this time. To the projecting ends of the shaft 13 are fixed the operating levers 14, and the outer ends of these levers are joined by a rod 15 to form the operating handle by which the shaft 13 may be rotated. Rotatable upon the rod 15 is a roller 16 adapted to engage the curved upper surface 17 of the hinge arm 7 when the handle is moved about the axis of said shaft. The proportions of these parts are such that the handle 16 can not be rotated from its open circuit position to its closed circuit position until the cover plate has been moved into protective position within the opening of the top wall 2 of the casing.

It will be noted that the curved upper surface 17 of hinge arm 7 is substantially in the shape of an are having the axis of shaft 13 as a center when the cover is closed. When the handle is moved to open the switch, roller 16 will thus have prolonged contact with surface 17 so that the cover will by no possibility be released from fully closed position before switch members 18 and 19 have fully separated.

Attached to the shaft 13 and rotatable therewith, but electrically insulated therefrom is a switch blade 18 adapted, when the operating handle is in its forward, or closed circuit position, to engage the contact brush 19 to form an electric connection therewith. The switch blade 18 and contact brush are suitably supported upon an insulating base 20 and may beconnected with any preferred electric circuit through the conductors 21 which enter the casing glands 22 in the manner which is well understood in the art.

When the cover plate 3 is in place in the opening of the top wall 2, and the switch handle 14 is in forward, or closed circuit position, the electric circuit with which the conductors 21 are connected, is closed by the contact of the blade 18 with the brush 19, and the casing is at the same time securely closed to prevent communication between the atmosphere within and that surrounding the casing. When the handlev 14 is moved rearwardly, towards'its open circuit position, the cover plate 3 is not released for movement outwardly of the casing until after the movement of the blade 18 away from the brush 19 has interrupted the circuit, thus preventing the possibility of the formation of electric arcs between said blade and said brush.

While threaded engagement of the cover plate 3 with the top wall 2 of the casing, such as illustrated in Figs. 2 and 3, of the drawings, is generally desirable, it is not essential, and in Fig. 4, I have shown such a casing wherein the cover plate 23 is formed with a straight tapering edge adapted to fit a tapering seat 24 in the top wall 25. In such a construction pivoting of the cover plate upon the hinge arm 26 is unnecessary, and after the switch handle 16 has been moved to its open circuit position, the cover plate may be lifted, in parallelism, out of the seat 24 and swung back as above described. In such a construction, exclusive dependence is had upon the switch handle 16 to hold the cover plate 23 in its place when the electric circuit is closed.

It is to be understood that the device herein described may be subjected to very considerable modification without departure from the spirit of my invention.

What I claim is:

1. In an apparatus of the class described, the combination with a casing having a cir-- cular aperture extending through its wall, of a circular closure screw threaded into said aperture, an electric circuit breaker within the casing, a handle outside of said casing operatively connected with said circuit breaker and adapted when in closed circuit position to engage over the closure to pre' vent movement of said closure outwardly of said casing.

2. In an apparatus of the class described,"

the combination with a casing having a. circular aperture extending through its wall, of a circular closure screw threaded into said aperture, a member hinged to said casing and pivotally connected to said closure to permit its movement to and from closed position, an electric circuit breaker within said casing, a

'handle outside of said casing and operatively connected with said circuit breaker adapted when in closed circuit position to engage over the closure to prevent movement of said closure outwardly of said aperture as and for the purpose set forth.

3. In a device of the class described, a casing having an aperture, a closure element for said aperture initially removable from the latter in a constrained rectilinear movement directly away from said casing, hinge means connecting the closure element and the casing and accommodating closing and removal movements of said closure, a lever pivoted to said casing, means movable upon operation of said lever in one direction to engage the closure element to prevent removal of the latter and upon operation of the lever in the opposite direction to release said element, and an electric circuit breaker within said casing closed when the lever is in locking position relative to the closure element and opened when the latter is released.

4. In a device of the class described, :1 casing having an aperture, a removable closure element for said aperture, a hinge arm connecting said casing and closure element and extending over a portion of the outer face of the latter, a lever pivoted to said casing, a handle on the free end of the said lever adapted to swing over the closure element, said arm having a portion uniformly engaged by said handle throughout a substantial angle of movement of said lever to secure the closure element in closed position, and an electric circuit breaker within the casing operated during said angular movement of the lever.

5. In an apparatus of the class described, a casing having a walled aperture therein, a removable closure for said aperture having a peripheral surface adapted in the closed position of the closure to extend into said aperture in sealing relation with the aperture walls, hinge means connecting the closure and the casing and accommodating closing and removal movements of said closure, an electric circuit breaker within the casing, a handle outside the casing operatively connected with the circuit breaker and adapted when in closed circuit position to prevent movement of said closure outwardly of said casing.

In testimony whereof I have hereunto set In hand.

y WALTER J. BAUROTH. 

